Pep ACIE eke 
LINGULA) ATBA-PINENSIS 2.202225 cn ecim cee amininn (e amna ate mint emia tele == ela le eg = alee lola iat 
Fig.1. Broad form, enlarged to six diameters. 
la. Elongate form, enlarged to six diameters. 
LINGULA LIGEA ...-..-.---------- -- BE BOON Bate ochre caso Cn QO OSC Ded Sone I Seno Sos IMEC Sam cS 
Fig. 2. A typical specimen, enlarged to two diameters. , 
LINGUA JUIGEA, var., NEVADENSIS = om = oc ate weit ain mm elm altel petal ein mm elie 
Fig. 3. Specimen showing the more attenuate form, as compared with fig. 2. Enlarged to 
two diameters. 
Vids (Cio) 67 AN IO Ole Soar CeCe eect OS0scH 9050 GuaU Com ea doS S55 saan aesancocdeeescocSansesencoss 
Fig. 4, A distorted specimen. Natural size. e 
IDISCINAS IGODENSIS) oie ayea cnet oa ae rata ale oer tae lle orate eee pelo latte ete ee ata ott eel a 
Fig.5. Ventral valve. Natural size. 
5a. Dorsal valve. Natural size. 
1247 COMODO) LINO NO00) WneaaooEoreoeas ocbee COD SOSb aa se Sane SoG sons cambousitos cada ceececaso 
Fig.6. Ventral valve, enlarged to six diameters. 
6a. Cast of interior of ventral valve, enlarged to six diameters. 
6b. Interior of ventral valve, enlarged to six diameters. 
PHOLIDOPS| QUADRANG ULARIS oi oo = 0lmie| oa at ate = wal miin ele mel ets lel ol intel etler «fa melanie) = oteteletetetottelar 
Fig. 7. Enlargement to three diameters of the type specimen. 
GFONE TIS UB ERG TA 6 a oo im oe ata wre tmp ale miele mmm me wil ld el 
Figs. 8, 8a, 8b. Medium, transverse, and short forms of the ventral valve. Nataral size. 
STROPHODONTA DEMISSA....- ~~ 222+ 2+ 0-22 = ee ene cone ne eee cee ce enn eens wn es eee ee en weee 
Figs. 9, 9a, 9b. Lateral, ventral, and dorsal views of a specimen from Lone Mountain. 
PRODUCTOS HERS U DUE OR MB es eterno eae feta ett ee lear 
Fig. 10. Enlargement to three diameters of a small ventral valve, preserving three of the 
slender surface spines. 
10a. A large ventral valve, showing a portion of the outer shell and cast of the inner 
surface, 
STROPHODONTASINEQUIRA DIANA sere cose eis else se a ae aaa eels el eee eee eee 
Fig. 11. A strongly-marked fragment of the ventral valve. 
lla. Enlargement of the surface of fig. 11. 
ORTHIS TULLIENSIS ...--. .--- <5 22-2 n = oo none renee oe coer oe wenn we nee mene ewe nn nnn enn cces 
Figs. 12,12a. Lateral and ventral view of an average size specimen. 
CHONETES MACROSTRIATA 
Fig. 13. Dorsal view. Natural size. See plate xiii, figs. 14, 14a-c. 
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